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<head><meta charset="utf-8"><title>meeting time · project-ffi-unwind · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/index.html">project-ffi-unwind</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html">meeting time</a></h3>

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<a name="177769270"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177769270" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177769270">(Oct 10 2019 at 00:39)</a>:</h4>
<p>I forget, <span class="user-group-mention" data-user-group-id="1866">@WG-ffi-unwind</span>, did we plan on having another meeting? And if so, when? I remember we said that <span class="user-mention" data-user-id="120076">@Kyle Strand</span> was going to prep a new RFC, based on the outline we had prepared?</p>



<a name="177770478"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177770478" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177770478">(Oct 10 2019 at 01:02)</a>:</h4>
<p>I think it might be appropriate to announce the group before drafting the new RFC. I suppose we can also submit the actual RFC PR in a WIP state like I did for 2753, though.</p>



<a name="177770483"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177770483" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177770483">(Oct 10 2019 at 01:02)</a>:</h4>
<p>I don't think we had specific meeting plans.</p>



<a name="177807818"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177807818" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177807818">(Oct 10 2019 at 13:09)</a>:</h4>
<p>I'm fine either way. I envisioned the RFC as "proposing" the group, so it kind of doubles as an announcement, but I think we could also post something on the Inside Rust blog. Could probably adapt my post.</p>



<a name="177807832"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177807832" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177807832">(Oct 10 2019 at 13:09)</a>:</h4>
<p>I'd mostly like to have a set of steps we are following, because I'm feeling a bit lost as to what is happening</p>



<a name="177827505"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177827505" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177827505">(Oct 10 2019 at 16:28)</a>:</h4>
<p>I'm a bit lost as well, but the primary cause is I've been dragged away to work on other things all week. However, some of that has been relevant, like chatting with <span class="user-mention" data-user-id="116015">@Alex Crichton</span> about unwinding generally. maybe we should have a Zulip meeting to get realigned?</p>



<a name="177841131"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177841131" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177841131">(Oct 10 2019 at 18:46)</a>:</h4>
<p>Well, the repo now has a set of steps to take - I just haven't made any progress on them.</p>



<a name="177841178"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177841178" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177841178">(Oct 10 2019 at 18:46)</a>:</h4>
<p>Maybe they need to be more concrete?</p>



<a name="177841207"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177841207" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177841207">(Oct 10 2019 at 18:46)</a>:</h4>
<h2>Current action items</h2>
<ol>
<li>
<p>Make a <a href="http://charter.md" target="_blank" title="http://charter.md">draft charter</a> for the project<br>
    * "enable stable unwinding across FFI boundaries"</p>
</li>
<li>
<p>Create a Zulip channel (need Niko or another Zulip admin to do this, I think)</p>
</li>
<li>Close RFCs <a href="https://github.com/rust-lang/rust/issues/2753" target="_blank" title="https://github.com/rust-lang/rust/issues/2753">#2753</a> and <a href="https://github.com/rust-lang/rust/issues/2699" target="_blank" title="https://github.com/rust-lang/rust/issues/2699">#2699</a> and point to this repository and the Zulip channel</li>
<li>
<p>Create design documents and drafts in this repo</p>
<ul>
<li>create a "sketch" document to start, fill it in over time</li>
</ul>
</li>
<li>
<p>Create issues for the outstanding concerns</p>
<ul>
<li>lock issues that are not the current focus topic?</li>
<li>unsafe code guidelines just used "focus" labels, maybe do that</li>
<li>or maybe use time-based issues (woah!) where the sync meeting marks a<br>
   "pause" to collect, incorporate new findings, and set new topics</li>
</ul>
</li>
</ol>



<a name="177841221"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177841221" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177841221">(Oct 10 2019 at 18:46)</a>:</h4>
<p>I think we can even cross the first one off</p>



<a name="177841390"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177841390" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177841390">(Oct 10 2019 at 18:48)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> Sounds like we don't really have an update this week; should I skip the lang team call?</p>



<a name="177849912"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177849912" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177849912">(Oct 10 2019 at 20:21)</a>:</h4>
<p>This seems good</p>



<a name="177850023"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177850023" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177850023">(Oct 10 2019 at 20:22)</a>:</h4>
<p>I think we should do a zulip meeting, yeah</p>



<a name="177850029"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177850029" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177850029">(Oct 10 2019 at 20:22)</a>:</h4>
<p>It probably makes sense to make a kind of regular-ish meeting time?</p>



<a name="177850037"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177850037" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177850037">(Oct 10 2019 at 20:22)</a>:</h4>
<p>At least until we feel like things are progressing?</p>



<a name="177850657"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177850657" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177850657">(Oct 10 2019 at 20:29)</a>:</h4>
<p>Have you started poking at the newer RFC text at all, <span class="user-mention" data-user-id="120076">@Kyle Strand</span> ?</p>



<a name="177851849"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177851849" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177851849">(Oct 10 2019 at 20:44)</a>:</h4>
<p>I have not, sorry. I did look at the draft in the repo and see that the RFC summary matched the notes you had written up last time we talked synchronously</p>



<a name="177852022"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177852022" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177852022">(Oct 10 2019 at 20:46)</a>:</h4>
<p>that sounds good to me; I am fine with continuing to meet on Thursday mornings, but am fairly open if y'all would prefer something else</p>



<a name="177852086"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177852086" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177852086">(Oct 10 2019 at 20:47)</a>:</h4>
<p>Wednesday might be good in case we want to execute an action item prior to checking in with the lang team.</p>



<a name="177852109"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177852109" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177852109">(Oct 10 2019 at 20:47)</a>:</h4>
<p>Otherwise, maybe meeting _after_ the lang team meeting (like...right now?) would be better</p>



<a name="177907661"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177907661" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177907661">(Oct 11 2019 at 13:43)</a>:</h4>
<p>OK <span class="user-group-mention" data-user-group-id="1866">@WG-ffi-unwind</span> so I was taking a stab at trying to "organize" our roadmap in a way that could be easily understood. I'm curious what you think of <a href="https://hackmd.io/taEITUbYTwOvbPtdvJTjpw" target="_blank" title="https://hackmd.io/taEITUbYTwOvbPtdvJTjpw">the table in this hackmd</a> -- I think this would eventually move to the repository's main README. </p>
<p>The idea would be that:</p>
<ul>
<li>each of the things in there is a link taking you to a README that links to relevant discussion, key decisions, RFCs, etc.</li>
<li>we can refine rows as needed or add more columns. I am assuming in particular that we will have to approach all the "tier 1" targets  separately, since I'm sure they each have their own unique complications.</li>
</ul>



<a name="177907718"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177907718" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177907718">(Oct 11 2019 at 13:44)</a>:</h4>
<p>Also, <span class="user-mention" data-user-id="132920">@gnzlbg</span>, are you in that alias above (and do you want to be?) <span aria-label="point up" class="emoji emoji-1f446" role="img" title="point up">:point_up:</span> I think you can add yourself, but if not I can add you.</p>



<a name="177924687"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177924687" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177924687">(Oct 11 2019 at 16:35)</a>:</h4>
<p>What is the difference between "unwind from X to Y" and "propagate X [unwind] through Y"? Are the rows starting with "propagate" just sub-cases of the rows starting with "unwind from"?</p>



<a name="177924798"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177924798" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177924798">(Oct 11 2019 at 16:36)</a>:</h4>
<p>Also, I think we should just say "out of scope" rather than "likely never supported", just because AFAIK there's no intent to close off the possibility of extending what can be done to other platforms</p>



<a name="177924844"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177924844" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177924844">(Oct 11 2019 at 16:37)</a>:</h4>
<p>"out of scope for foreseeable future" seems fine</p>



<a name="177924866"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177924866" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177924866">(Oct 11 2019 at 16:38)</a>:</h4>
<blockquote>
<p>What is the difference between "unwind from X to Y" and "propagate X [unwind] through Y"? Are the rows starting with "propagate" just sub-cases of the rows starting with "unwind from"?</p>
</blockquote>
<p>maybe there is no difference</p>



<a name="177945299"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177945299" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177945299">(Oct 11 2019 at 20:20)</a>:</h4>
<p>OK I <a href="https://github.com/nikomatsakis/project-ffi-unwind/pull/7" target="_blank" title="https://github.com/nikomatsakis/project-ffi-unwind/pull/7">prepared a PR</a> sketching this out in more detail. <span class="user-group-mention" data-user-group-id="1866">@WG-ffi-unwind</span> what do y'all think?</p>



<a name="177948780"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177948780" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177948780">(Oct 11 2019 at 20:57)</a>:</h4>
<p>this looks fantastic! (except I'm Adam not Alex <span aria-label="wink" class="emoji emoji-1f609" role="img" title="wink">:wink:</span>)</p>



<a name="177949841"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177949841" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177949841">(Oct 11 2019 at 21:11)</a>:</h4>
<p>I left a few comments on the PR, but I'm overall very happy with this</p>



<a name="177950379"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950379" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950379">(Oct 11 2019 at 21:18)</a>:</h4>
<p>what the heck</p>



<a name="177950382"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950382" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950382">(Oct 11 2019 at 21:18)</a>:</h4>
<p>did I write Alex somewhere?</p>



<a name="177950387"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950387" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950387">(Oct 11 2019 at 21:18)</a>:</h4>
<p>I'm too used to Alex Crichton</p>



<a name="177950409"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950409" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950409">(Oct 11 2019 at 21:18)</a>:</h4>
<p>hehe, I figured :) it's at the top of the readme, not in that PR though</p>



<a name="177950452"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950452" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950452">(Oct 11 2019 at 21:19)</a>:</h4>
<p>ok ok</p>



<a name="177950801"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950801" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950801">(Oct 11 2019 at 21:23)</a>:</h4>
<p>applied your edits</p>



<a name="177950814"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950814" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950814">(Oct 11 2019 at 21:23)</a>:</h4>
<p>ps, in the future, you can make "suggestions" where you edit the line yourself in gh pretty easily</p>



<a name="177950817"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950817" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950817">(Oct 11 2019 at 21:23)</a>:</h4>
<p>which then allows me to apply them very easily</p>



<a name="177950869"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950869" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950869">(Oct 11 2019 at 21:24)</a>:</h4>
<p>"suggestions" are my new favorite GitHub feature</p>



<a name="177950872"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950872" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950872">(Oct 11 2019 at 21:24)</a>:</h4>
<p><a href="https://help.github.com/en/articles/incorporating-feedback-in-your-pull-request" target="_blank" title="https://help.github.com/en/articles/incorporating-feedback-in-your-pull-request">https://help.github.com/en/articles/incorporating-feedback-in-your-pull-request</a></p>



<a name="177950875"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950875" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950875">(Oct 11 2019 at 21:24)</a>:</h4>
<p>yeah, they're awesome</p>



<a name="177950935"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950935" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950935">(Oct 11 2019 at 21:25)</a>:</h4>
<p>Looks like I was probably the one responsible for "Alex", even though I asked in advance if "Adam" was okay! Sorry!</p>



<a name="177950940"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950940" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950940">(Oct 11 2019 at 21:25)</a>:</h4>
<p>I must be missing the UI that allows that? maybe it's based on repo permissions?</p>



<a name="177950944"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950944" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950944">(Oct 11 2019 at 21:25)</a>:</h4>
<p>hah, no worries :)</p>



<a name="177950967"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950967" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950967">(Oct 11 2019 at 21:25)</a>:</h4>
<blockquote>
<p>I must be missing the UI that allows that? maybe it's based on repo permissions?</p>
</blockquote>
<p>could be</p>



<a name="177950974"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177950974" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177950974">(Oct 11 2019 at 21:25)</a>:</h4>
<p>I should probably add y'all as collaborators</p>



<a name="177951025"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177951025" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177951025">(Oct 11 2019 at 21:26)</a>:</h4>
<p>but I'll hold off slightly, I plan to transfer this to rust-lang</p>



<a name="177951035"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177951035" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177951035">(Oct 11 2019 at 21:26)</a>:</h4>
<p>and create a proper rust team</p>



<a name="177951043"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177951043" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177951043">(Oct 11 2019 at 21:26)</a>:</h4>
<p>then I can give the permissions to that team, which is the new way to do things</p>



<a name="177951054"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177951054" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177951054">(Oct 11 2019 at 21:26)</a>:</h4>
<p>sounds good</p>



<a name="177951057"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177951057" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177951057">(Oct 11 2019 at 21:26)</a>:</h4>
<p>anyway I'll merge that PR I think</p>



<a name="177951130"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177951130" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177951130">(Oct 11 2019 at 21:27)</a>:</h4>
<p>woops, readme looks a bit funny, but basically good :)</p>



<a name="177952626"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177952626" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177952626">(Oct 11 2019 at 21:46)</a>:</h4>
<p>I submitted a late review b/c it's mostly questions and other things that can be addressed in one or more future PRs</p>



<a name="177952640"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177952640" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177952640">(Oct 11 2019 at 21:47)</a>:</h4>
<p>(Also b/c I had already written up the individual comments without noticing that you'd merged)</p>



<a name="177953293"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177953293" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177953293">(Oct 11 2019 at 21:56)</a>:</h4>
<p><span class="user-mention" data-user-id="120076">@Kyle Strand</span> I left responses -- mostly I think your suggested changes are good, maybe open a PR?</p>



<a name="177953295"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177953295" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177953295">(Oct 11 2019 at 21:56)</a>:</h4>
<p>one question is about my use of the term "undefiend behavior"</p>



<a name="177953302"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177953302" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177953302">(Oct 11 2019 at 21:56)</a>:</h4>
<p>I don't really see the point of trying to find some other, more precise term.</p>



<a name="177953315"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177953315" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177953315">(Oct 11 2019 at 21:57)</a>:</h4>
<p>but i'm not opposed if you have one in mind :)</p>



<a name="177953323"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177953323" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177953323">(Oct 11 2019 at 21:57)</a>:</h4>
<p>at the end of the day though it seems like UB is..well.. what it is.</p>



<a name="177953326"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177953326" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177953326">(Oct 11 2019 at 21:57)</a>:</h4>
<p>(not <em>LLVM</em> UB, to be clear)</p>



<a name="177953334"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177953334" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177953334">(Oct 11 2019 at 21:57)</a>:</h4>
<p>(and it might be worth clarifying that difference)</p>



<a name="177953355"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/177953355" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#177953355">(Oct 11 2019 at 21:57)</a>:</h4>
<p>gotta run</p>



<a name="178274729"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178274729" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178274729">(Oct 16 2019 at 10:03)</a>:</h4>
<p>OK <span class="user-group-mention" data-user-group-id="1866">@WG-ffi-unwind</span> -- we should setup a time for a brief sync. I'm feeling quite disorganized here. Previously we did Thu at 1pm and <span class="user-mention" data-user-id="237472">@Adam C. Foltzer</span> you said that worked for you? I could work with that. Ideally it'd be 30 minutes. It has the advantage of coming shortly before the lang team meeting.</p>
<p>To clarify what I see as the purpose of this --</p>
<ul>
<li>initially it would be to finish up with getting our plan organized, determining how we'll run group, etc</li>
<li>longer term, I think it would be to help "steer" the conversation -- creating summaries, preparing summary for lang team, etc</li>
</ul>



<a name="178306059"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178306059" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178306059">(Oct 16 2019 at 16:37)</a>:</h4>
<p>1pm in which time zone? One or two hours before the lang team meeting, right? I do want to continue to attend Release team meetings, so I'd like to avoid 11am-11:30am Mountain time. Those are pretty strictly timeboxed, though, so we could do 11:30am if we only need half an hour.</p>



<a name="178306095"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178306095" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178306095">(Oct 16 2019 at 16:37)</a>:</h4>
<p>(I apologize if some or all of the "feeling disorganized" is on me!)</p>



<a name="178306298"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178306298" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178306298">(Oct 16 2019 at 16:40)</a>:</h4>
<p>30 minutes should suffice</p>



<a name="178306308"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178306308" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178306308">(Oct 16 2019 at 16:40)</a>:</h4>
<p>I meant 1pm in "US Eastern time"</p>



<a name="178306313"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178306313" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178306313">(Oct 16 2019 at 16:40)</a>:</h4>
<p>So maybe 13:30 US Eastern time?</p>



<a name="178317156"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178317156" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178317156">(Oct 16 2019 at 18:41)</a>:</h4>
<p>I am down for 17:30 UTC <span aria-label="wink" class="emoji emoji-1f609" role="img" title="wink">:wink:</span></p>



<a name="178317242"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178317242" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178317242">(Oct 16 2019 at 18:42)</a>:</h4>
<p><a href="/user_uploads/4715/oNidqOSPYPY4iJHBKZMANkr4/pasted_image.png" target="_blank" title="pasted_image.png">pasted image</a></p>
<div class="message_inline_image"><a href="/user_uploads/4715/oNidqOSPYPY4iJHBKZMANkr4/pasted_image.png" target="_blank" title="pasted image"><img src="/user_uploads/4715/oNidqOSPYPY4iJHBKZMANkr4/pasted_image.png"></a></div>



<a name="178317277"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178317277" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178317277">(Oct 16 2019 at 18:42)</a>:</h4>
<p>I have a huge backlog on messages in this stream, which I will try to burn through this afternoon</p>



<a name="178318040"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178318040" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178318040">(Oct 16 2019 at 18:51)</a>:</h4>
<p>I don't like to use UTC as my point of reference because I want it to track US Daylight Savings time :)</p>



<a name="178318097"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178318097" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178318097">(Oct 16 2019 at 18:52)</a>:</h4>
<p>(which, at least for now, still aligns with most of Europe, apart from a few weeks in the year -- though I guess that may change...)</p>



<a name="178318111"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178318111" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178318111">(Oct 16 2019 at 18:52)</a>:</h4>
<p>but yeah :) helpful</p>



<a name="178324616"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178324616" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178324616">(Oct 16 2019 at 20:16)</a>:</h4>
<p>yeah, I was just being a smartass, don't mind me. time zones are hard</p>



<a name="178324796"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178324796" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178324796">(Oct 16 2019 at 20:18)</a>:</h4>
<p>OK I'm going to create an entry on the lang team calendar</p>



<a name="178324819"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178324819" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178324819">(Oct 16 2019 at 20:19)</a>:</h4>
<p>I don't see this group being one that requires a <em>lot</em> of compiler interaction, so it seems "more" just lang</p>



<a name="178324824"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178324824" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178324824">(Oct 16 2019 at 20:19)</a>:</h4>
<p>maybe those should just be one calendar</p>



<a name="178324826"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178324826" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178324826">(Oct 16 2019 at 20:19)</a>:</h4>
<p>anyway</p>



<a name="178324931"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178324931" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178324931">(Oct 16 2019 at 20:20)</a>:</h4>
<p><a href="https://calendar.google.com/event?action=TEMPLATE&amp;tmeid=MG8zcXU5c2M2NTY0bmtrYjUwdjJoN2Q0MmsgcmVjdWQ0YjlvOGNtYzBtNXJtcjAzM3A1bmtAZw&amp;tmsrc=recud4b9o8cmc0m5rmr033p5nk%40group.calendar.google.com" target="_blank" title="https://calendar.google.com/event?action=TEMPLATE&amp;tmeid=MG8zcXU5c2M2NTY0bmtrYjUwdjJoN2Q0MmsgcmVjdWQ0YjlvOGNtYzBtNXJtcjAzM3A1bmtAZw&amp;tmsrc=recud4b9o8cmc0m5rmr033p5nk%40group.calendar.google.com">Event published</a></p>



<a name="178403125"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403125" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403125">(Oct 17 2019 at 17:34)</a>:</h4>
<p><span class="user-mention" data-user-id="*">@stream</span>  (that just notifies wg-ffi-unwind participants, correct?) - did we have a Zoom link?</p>



<a name="178403149"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403149" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403149">(Oct 17 2019 at 17:34)</a>:</h4>
<p>Mm I thnk you want <span class="user-group-mention" data-user-group-id="1866">@WG-ffi-unwind</span> =)</p>



<a name="178403158"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403158" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403158">(Oct 17 2019 at 17:34)</a>:</h4>
<p>I was figuring we'd do the meeting on Zulip</p>



<a name="178403166"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403166" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403166">(Oct 17 2019 at 17:35)</a>:</h4>
<p>But we could do Zoom if desired</p>



<a name="178403190"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403190" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403190">(Oct 17 2019 at 17:35)</a>:</h4>
<p>the help pop-up did say "channel", not... whatever <code>rust-lang</code> is (edit: I wanted <code>@stream</code>)</p>



<a name="178403195"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403195" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403195">(Oct 17 2019 at 17:35)</a>:</h4>
<p>Zulip works for me</p>



<a name="178403213"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403213" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403213">(Oct 17 2019 at 17:35)</a>:</h4>
<p>Should we start with some brief updates?</p>



<a name="178403281"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403281" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403281">(Oct 17 2019 at 17:36)</a>:</h4>
<p>Yes please, seems like there's been a lot</p>



<a name="178403294"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403294" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403294">(Oct 17 2019 at 17:36)</a>:</h4>
<p>It has been active!</p>



<a name="178403310"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403310" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403310">(Oct 17 2019 at 17:36)</a>:</h4>
<p>OK, so, first off -- <span class="user-mention" data-user-id="132920">@gnzlbg</span> and I seem to have hammered out terminology we are both happy with</p>



<a name="178403327"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403327" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403327">(Oct 17 2019 at 17:36)</a>:</h4>
<p>In particular:</p>



<a name="178403340"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403340" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403340">(Oct 17 2019 at 17:36)</a>:</h4>
<ul>
<li>Undefined Behavior -- we share this w/ the unsafe code guidelines folks</li>
</ul>



<a name="178403352"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403352" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403352">(Oct 17 2019 at 17:37)</a>:</h4>
<p>basically refers to a "panic" in the "virtual machine" that executes rust, so to speak</p>



<a name="178403375"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403375" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403375">(Oct 17 2019 at 17:37)</a>:</h4>
<p>Side question: that seems a bit counter-intuitive to me, so I'm guessing I don't quite understand what that means.</p>



<a name="178403381"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403381" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403381">(Oct 17 2019 at 17:37)</a>:</h4>
<ul>
<li>Unspecified Behavior -- behavior where we don't say what it is does, or perhaps it's platform dependent etc, but it's not an <em>error</em>.</li>
</ul>



<a name="178403388"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403388" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403388">(Oct 17 2019 at 17:37)</a>:</h4>
<p>I think of "panic" as being always well-defined</p>



<a name="178403422"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403422" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403422">(Oct 17 2019 at 17:38)</a>:</h4>
<p>maybe best is to just check the <a href="https://github.com/nikomatsakis/project-ffi-unwind/blob/master/spec-terminology.md" target="_blank" title="https://github.com/nikomatsakis/project-ffi-unwind/blob/master/spec-terminology.md">page that we updated</a></p>



<a name="178403474"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403474" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403474">(Oct 17 2019 at 17:38)</a>:</h4>
<p>I am currently reviewing</p>



<a name="178403483"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403483" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403483">(Oct 17 2019 at 17:38)</a>:</h4>
<p>the tricky and somewhat subtle bit is that both undefined behavior and unspecified behavior ultimately have somewhat arbitrary results :)</p>



<a name="178403493"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403493" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403493">(Oct 17 2019 at 17:38)</a>:</h4>
<p>^ yes</p>



<a name="178403494"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403494" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403494">(Oct 17 2019 at 17:38)</a>:</h4>
<p>for our purposes, though, I think we're largely dealing with <em>unspecified behavior</em></p>



<a name="178403504"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403504" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403504">(Oct 17 2019 at 17:38)</a>:</h4>
<p>Agreed</p>



<a name="178403510"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403510" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403510">(Oct 17 2019 at 17:38)</a>:</h4>
<p>Or, ought to be</p>



<a name="178403524"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403524" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403524">(Oct 17 2019 at 17:38)</a>:</h4>
<p>the one final bit is that we settled on the term To Be Defined</p>



<a name="178403532"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403532" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403532">(Oct 17 2019 at 17:39)</a>:</h4>
<p>to refer to behavior that is currently unspecified</p>



<a name="178403539"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403539" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403539">(Oct 17 2019 at 17:39)</a>:</h4>
<p>but which this group expects to specify :)</p>



<a name="178403561"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403561" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403561">(Oct 17 2019 at 17:39)</a>:</h4>
<p>so e.g. we might say that certain aspects of how a Rust panic propagates across a "C unwind" are TBD</p>



<a name="178403570"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403570" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403570">(Oct 17 2019 at 17:39)</a>:</h4>
<p>or whatever</p>



<a name="178403661"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403661" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403661">(Oct 17 2019 at 17:40)</a>:</h4>
<p>finally, I wrote up a <a href="https://github.com/nikomatsakis/project-ffi-unwind/blob/master/resolved-concerns/2019-10-17-tbd-on-stable.md" target="_blank" title="https://github.com/nikomatsakis/project-ffi-unwind/blob/master/resolved-concerns/2019-10-17-tbd-on-stable.md">document outlining the tradeoffs around exposing TBD behavior on stable</a>, and I think at this point we all agree it (can) make sense to do so</p>



<a name="178403742"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403742" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403742">(Oct 17 2019 at 17:41)</a>:</h4>
<p>I think that's something we should double check at the lang team meeting, but my understanding was that this was something that we all agreed made sense</p>



<a name="178403749"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403749" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403749">(Oct 17 2019 at 17:41)</a>:</h4>
<blockquote>
<p>for "official" purposes, all TBD behavior is simply unspecified.</p>
</blockquote>
<p>Would it be reasonable to explicitly say in this documentation: whenever new "TBD" functionality hits stable, it will be considered "unspecified"?</p>



<a name="178403760"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403760" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403760">(Oct 17 2019 at 17:41)</a>:</h4>
<p>I.e. in some official capacity, such as the Reference</p>



<a name="178403907"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403907" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403907">(Oct 17 2019 at 17:43)</a>:</h4>
<blockquote>
<p>Would it be reasonable to explicitly say in this documentation: whenever new "TBD" functionality hits stable, it will be considered "unspecified"?</p>
</blockquote>
<p>I did say that</p>



<a name="178403937"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178403937" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178403937">(Oct 17 2019 at 17:43)</a>:</h4>
<blockquote>
<p>This designation is not part of the "Rust reference" -- for "official" purposes, all TBD behavior is simply unspecified.</p>
</blockquote>



<a name="178404028"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404028" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404028">(Oct 17 2019 at 17:44)</a>:</h4>
<p>these look great; in particular the distinctions between UB/LLVM-UB and unspecified/TBD get to the heart of a lot of the miscommunications I've seen as we've discussed this topic</p>



<a name="178404077"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404077" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404077">(Oct 17 2019 at 17:44)</a>:</h4>
<p>the other major developiment is that we have two distinct takes on the "0th" RFC ;)</p>



<a name="178404080"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404080" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404080">(Oct 17 2019 at 17:44)</a>:</h4>
<p>(seen/been a culprit of <span aria-label="wink" class="emoji emoji-1f609" role="img" title="wink">:wink:</span>)</p>



<a name="178404134"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404134" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404134">(Oct 17 2019 at 17:45)</a>:</h4>
<p>I wrote a fairly minimal one, and <span class="user-mention" data-user-id="132920">@gnzlbg</span> has a somewhat more expansive one. To be honest they're not that far apart, and I'll probably just try to steal a lot of their text -- it's basically making <em>more</em> promises than mine.</p>



<a name="178404147"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404147" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404147">(Oct 17 2019 at 17:45)</a>:</h4>
<p>I mostly didn't do that because I was being careful</p>



<a name="178404176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404176">(Oct 17 2019 at 17:45)</a>:</h4>
<p>I don't quite know how many "unknown unknowns" there are...</p>



<a name="178404190"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404190" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404190">(Oct 17 2019 at 17:45)</a>:</h4>
<p>at some point maybe I'll actually read the itanium spec ;)</p>



<a name="178404203"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404203" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404203">(Oct 17 2019 at 17:45)</a>:</h4>
<p>My only concern with more promises is that I got the sense that the lang team (especially Centril, I think) would prefer fewer promises wherever possible</p>



<a name="178404256"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404256" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404256">(Oct 17 2019 at 17:46)</a>:</h4>
<p>I still haven't had time to do a careful reading, but am I correct in surmising that <span class="user-mention" data-user-id="132920">@gnzlbg</span>'s version commits us to being 100% compliant with the ABI?</p>



<a name="178404265"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404265" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404265">(Oct 17 2019 at 17:46)</a>:</h4>
<p>And I think that's generally reasonable</p>



<a name="178404275"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404275" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404275">(Oct 17 2019 at 17:46)</a>:</h4>
<p>"the ABI"?</p>



<a name="178404320"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404320" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404320">(Oct 17 2019 at 17:47)</a>:</h4>
<p>I'm also quite comfortable starting with the minimal one -- we'll add syntax, but we're not specifying any of the details yet -- and then do a follow-up that <em>just</em> talks about (e.g.) specifying linux</p>



<a name="178404321"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404321" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404321">(Oct 17 2019 at 17:47)</a>:</h4>
<p>with the expectation that if the Rust panic mechanism ever changes, that we'll add shims to translate? sorry, the native unwinding ABI (eg DWARF/Itanium on SysV)</p>



<a name="178404330"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404330" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404330">(Oct 17 2019 at 17:47)</a>:</h4>
<p>oh, yes.</p>



<a name="178404334"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404334" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404334">(Oct 17 2019 at 17:47)</a>:</h4>
<p>my version also does.</p>



<a name="178404362"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404362" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404362">(Oct 17 2019 at 17:47)</a>:</h4>
<p>I think everybody is on board with that (including <span class="user-mention" data-user-id="239881">@Josh Triplett</span>, from our conversations)</p>



<a name="178404377"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404377" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404377">(Oct 17 2019 at 17:47)</a>:</h4>
<blockquote>
<p>my version also does.</p>
</blockquote>
<p>well, sort of -- mine says that once we specify a given platform, we have to stick to it :)</p>



<a name="178404398"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404398" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404398">(Oct 17 2019 at 17:47)</a>:</h4>
<p>and notes that this means that if we diverge our rust impl from the native one, the main thing we must do is provide some sort of bridge</p>



<a name="178404549"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404549" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404549">(Oct 17 2019 at 17:49)</a>:</h4>
<p>my main concern there is how that compatibility is scoped. if we're just saying that Rust unwinds with an ABI-compliant exception type using the system unwinding methods, I think that's fine because that's the implementation that exists today with <code>#[unwind(allowed)]</code>. however I would want to be clear that we are not fully ABI compliant until Rust treats foreign exceptions appropriately, which today it does not</p>



<a name="178404655"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404655" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404655">(Oct 17 2019 at 17:50)</a>:</h4>
<p>looking at the text now to see if this has already been addressed</p>



<a name="178404690"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404690" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404690">(Oct 17 2019 at 17:51)</a>:</h4>
<p>I think one thing that would be really helpful</p>



<a name="178404711"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404711" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404711">(Oct 17 2019 at 17:51)</a>:</h4>
<p>first of all, I think we should narrow to one platform at a time</p>



<a name="178404729"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404729" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404729">(Oct 17 2019 at 17:51)</a>:</h4>
<p>and I'd love it if we had an enumerate of the "knobs" we have to decide</p>



<a name="178404734"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404734" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404734">(Oct 17 2019 at 17:51)</a>:</h4>
<p>e.g., if look at itanium or whatever to call this ABI</p>



<a name="178404794"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404794" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404794">(Oct 17 2019 at 17:52)</a>:</h4>
<blockquote>
<p>we are not fully ABI compliant until Rust treats foreign exceptions appropriately, which today it does not</p>
</blockquote>
<p>I think independently of how this is specified (or not), it would be good to have some technical details on what the current implementation does. Would you feel comfortable writing those up somewhere? I have done a very small amount of testing and not noticed anything outright barbarous in Rust's behavior :D</p>



<a name="178404803"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404803" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404803">(Oct 17 2019 at 17:52)</a>:</h4>
<p>presumably, when a rust panic propagates, it has to "present itself" in various ways -- some kind of metadata, a string, whatever</p>



<a name="178404821"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404821" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404821">(Oct 17 2019 at 17:52)</a>:</h4>
<p>I'd sort of like to see that stuff enumerated out</p>



<a name="178404858"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404858" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404858">(Oct 17 2019 at 17:53)</a>:</h4>
<blockquote>
<p>I think independently of how this is specified (or not), it would be good to have some technical details on what the current implementation does. </p>
</blockquote>
<p>Yes, double this. That said, when I talked to <span class="user-mention" data-user-id="116015">@Alex Crichton</span> about this, it seemed like there were lots of complexities. It'd probably be good to try and narrow things down to individual platforms.</p>



<a name="178404879"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404879" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404879">(Oct 17 2019 at 17:53)</a>:</h4>
<p>Also I wonder if we should subscribe <span class="user-mention" data-user-id="116015">@Alex Crichton</span> to this stream -- I'm gonna do it :P</p>



<a name="178404887"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404887" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404887">(Oct 17 2019 at 17:53)</a>:</h4>
<p>most of it is only observable with <code>catch_unwind</code>, but yes</p>



<a name="178404914"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178404914" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178404914">(Oct 17 2019 at 17:53)</a>:</h4>
<p>I can help write up more about the gaps in the current implementation. I don't think they're very big</p>



<a name="178405064"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405064" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405064">(Oct 17 2019 at 17:55)</a>:</h4>
<blockquote>
<p>I'm gonna do it </p>
</blockquote>
<p>Alex can unsubscribe if so desired!</p>
<p>Also, I suspect RalfJung may be interested, though I don't know so.</p>



<a name="178405070"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405070" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405070">(Oct 17 2019 at 17:55)</a>:</h4>
<p>from <span class="user-mention" data-user-id="132920">@gnzlbg</span>'s proposal:</p>
<blockquote>
<p>whether such unwindings can always, sometimes, or never be caught with catch_unwind or not is target-dependent. If some of these unwindings that do not originate in Rust can be caught, their value is then of type std::panic::ForeignException (that is, the Result::Err(Any) that catch_unwind returns can be downcasted to such a type).</p>
</blockquote>
<p>I am very skeptical about including this capability at any point, but particularly for a 0th RFC it feels like too much</p>



<a name="178405175"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405175" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405175">(Oct 17 2019 at 17:56)</a>:</h4>
<p>Does <code>std::panic::ForeignException</code> already exist, or is that a proposed addition to <code>std</code>?</p>



<a name="178405185"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405185" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405185">(Oct 17 2019 at 17:56)</a>:</h4>
<p>proposed addition</p>



<a name="178405186"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405186" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405186">(Oct 17 2019 at 17:56)</a>:</h4>
<p>oh yeah I definitely did expect to remove that</p>



<a name="178405201"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405201" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405201">(Oct 17 2019 at 17:56)</a>:</h4>
<p>so I guess this is a good question</p>



<a name="178405211"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405211" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405211">(Oct 17 2019 at 17:56)</a>:</h4>
<p>I think the only thing I did specify in my version was</p>



<a name="178405212"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405212" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405212">(Oct 17 2019 at 17:56)</a>:</h4>
<p>Agreed, I think any suggestions for <code>std</code> features should be disqualified for RFC 0</p>



<a name="178405216"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405216" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405216">(Oct 17 2019 at 17:56)</a>:</h4>
<p>if you do this:</p>



<a name="178405218"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405218" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405218">(Oct 17 2019 at 17:56)</a>:</h4>
<p>perhaps for 0th we should commit to being an ABI-compliant <em>producer</em> of exceptions, but not necessarily an ABI-compliant <em>consumer</em></p>



<a name="178405230"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405230" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405230">(Oct 17 2019 at 17:57)</a>:</h4>
<div class="codehilite"><pre><span></span><span class="k">extern</span><span class="w"> </span><span class="s">&quot;C unwind&quot;</span><span class="w"> </span><span class="k">fn</span> <span class="nf">foo</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="n">panic</span><span class="o">!</span><span class="p">(</span><span class="s">&quot;foo&quot;</span><span class="p">)</span><span class="w"> </span><span class="p">}</span><span class="w"></span>

<span class="k">fn</span> <span class="nf">bar</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">  </span><span class="n">foo</span><span class="p">();</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>



<a name="178405233"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405233" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405233">(Oct 17 2019 at 17:57)</a>:</h4>
<p>it should interoperate as you expect</p>



<a name="178405262"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405262" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405262">(Oct 17 2019 at 17:57)</a>:</h4>
<p>which basically means: if there is a C unwind ABI, then you must have some way to convert Rust to native and back again</p>



<a name="178405265"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405265" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405265">(Oct 17 2019 at 17:57)</a>:</h4>
<blockquote>
<p>not necessarily an ABI-compliant consumer</p>
</blockquote>
<p>With the idea that we do at least expect Rust to be able to consume _its own_ <code>panic</code> objects, regardless of whether they traverse foreign frames</p>



<a name="178405271"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405271" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405271">(Oct 17 2019 at 17:57)</a>:</h4>
<p>but we don't say what those ways <em>are</em></p>



<a name="178405427"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405427" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405427">(Oct 17 2019 at 17:59)</a>:</h4>
<p>that sounds good. I just want to make sure we're not committing to doing anything sensible at all with foreign exceptions for the 0th RFC</p>



<a name="178405430"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405430" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405430">(Oct 17 2019 at 17:59)</a>:</h4>
<p>ok well it's been 30 minutes but maybe this is something we can bring to alng team</p>



<a name="178405440"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405440" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405440">(Oct 17 2019 at 17:59)</a>:</h4>
<ul>
<li>minimal start </li>
<li>follow-up?</li>
</ul>



<a name="178405443"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405443" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405443">(Oct 17 2019 at 17:59)</a>:</h4>
<p>the other thing is</p>



<a name="178405449"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405449" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405449">(Oct 17 2019 at 17:59)</a>:</h4>
<p>I think for now we should structure ourselves as doing a series of RFCs</p>



<a name="178405458"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405458" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405458">(Oct 17 2019 at 17:59)</a>:</h4>
<p>this is kind of what I proposed in my write-up</p>



<a name="178405520"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405520" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405520">(Oct 17 2019 at 18:00)</a>:</h4>
<p>but I did write that we have the expectation that, once we open an RFC, it has been through quite some vetting already</p>



<a name="178405540"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405540" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405540">(Oct 17 2019 at 18:00)</a>:</h4>
<p>so if you want to be involved in the more "formative phases", this group is the place to be</p>



<a name="178405546"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405546" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405546">(Oct 17 2019 at 18:00)</a>:</h4>
<p><span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span></p>



<a name="178405549"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405549" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405549">(Oct 17 2019 at 18:00)</a>:</h4>
<p>just a quick update on my stuff:<br>
- shared the note about my availability for the next ~month<br>
- trying to keep as up-to-date as possible with filling in details about Lucet use cases on Zulip<br>
- read about half of the PRs, very few of the PR comments</p>



<a name="178405587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405587">(Oct 17 2019 at 18:01)</a>:</h4>
<p>Probably also worth mentioning the use of "unspecified behavior" and the formal definition thereof, which I think might be a good thing to adopt in the Reference as well</p>



<a name="178405593"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405593" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405593">(Oct 17 2019 at 18:01)</a>:</h4>
<p>and to reiterate, I can make time for this but @ing me directly is a good way to make sure that I show up if my input is needed</p>



<a name="178405604"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405604" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405604">(Oct 17 2019 at 18:01)</a>:</h4>
<p>(mentioning to the Lang team, that is, since it affects them)</p>



<a name="178405624"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405624" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405624">(Oct 17 2019 at 18:01)</a>:</h4>
<blockquote>
<p>Probably also worth mentioning the use of "unspecified behavior" and the formal definition thereof, which I think might be a good thing to adopt in the Reference as well</p>
</blockquote>
<p>Yes. I think we should consider writing an RFC on this too -- just for the 'exposure'.</p>



<a name="178405634"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405634" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405634">(Oct 17 2019 at 18:01)</a>:</h4>
<p>Agreed</p>



<a name="178405638"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405638" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405638">(Oct 17 2019 at 18:01)</a>:</h4>
<p><span class="user-mention" data-user-id="120076">@Kyle Strand</span> do you plan to attend lang team mtg?</p>



<a name="178405641"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405641" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405641">(Oct 17 2019 at 18:01)</a>:</h4>
<p>Yes</p>



<a name="178405644"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405644" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405644">(Oct 17 2019 at 18:02)</a>:</h4>
<p>do you want to write up a bit of a summary with links to things?</p>



<a name="178405688"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405688" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405688">(Oct 17 2019 at 18:02)</a>:</h4>
<p>just a few bullet points</p>



<a name="178405692"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405692" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405692">(Oct 17 2019 at 18:02)</a>:</h4>
<p>Sure</p>



<a name="178405698"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405698" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405698">(Oct 17 2019 at 18:02)</a>:</h4>
<p>thanks all</p>



<a name="178405705"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405705" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405705">(Oct 17 2019 at 18:02)</a>:</h4>
<p><span aria-label="wave" class="emoji emoji-1f44b" role="img" title="wave">:wave:</span></p>



<a name="178405708"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405708" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405708">(Oct 17 2019 at 18:02)</a>:</h4>
<p>thank you all!</p>



<a name="178405724"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405724" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405724">(Oct 17 2019 at 18:02)</a>:</h4>
<p>thanks for all your time, both of you!</p>



<a name="178405735"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178405735" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178405735">(Oct 17 2019 at 18:02)</a>:</h4>
<p>"I'll give it right back to you one of these days" - Jimi</p>



<a name="178406886"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178406886" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178406886">(Oct 17 2019 at 18:16)</a>:</h4>
<blockquote>
<p>I am very skeptical about including this capability at any point, but particularly for a 0th RFC it feels like too much</p>
</blockquote>
<p>We kind of need to be able to do this anyways, e.g., to properly implement <code>catch_unwind</code>, see: <a href="https://github.com/rust-lang/rust/issues/65441" target="_blank" title="https://github.com/rust-lang/rust/issues/65441">https://github.com/rust-lang/rust/issues/65441</a></p>



<a name="178406907"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178406907" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178406907">(Oct 17 2019 at 18:16)</a>:</h4>
<p><span class="user-mention" data-user-id="143274">@Amanieu</span> said they also had other uses for this, maybe they can expand on those</p>



<a name="178407105"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178407105" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178407105">(Oct 17 2019 at 18:18)</a>:</h4>
<p>my understanding is that <code>catch (...)</code> blocks catching foreign exceptions in C++ is a feature that C++ folks regret</p>



<a name="178407183"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178407183" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178407183">(Oct 17 2019 at 18:19)</a>:</h4>
<p>On Linux, <code>&lt;exception&gt;</code> allows things like <code>catch (ada_exception const&amp; e)</code></p>



<a name="178407189"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178407189" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178407189">(Oct 17 2019 at 18:19)</a>:</h4>
<p>I agree with <span class="user-mention" data-user-id="143274">@Amanieu</span> in the linked thread:</p>
<blockquote>
<p>I feel that we should simply let all foreign exceptions unwind through catch_unwind without catching them.</p>
</blockquote>



<a name="178407191"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178407191" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178407191">(Oct 17 2019 at 18:19)</a>:</h4>
<p>so its not only <code>catch(...)</code> blocks</p>



<a name="178407292"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178407292" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178407292">(Oct 17 2019 at 18:20)</a>:</h4>
<p>If we say that unwinding with a foreign exception is UB, I think it would be a quality-of-implementation bug not to report a run-time error on UB in those platforms where we can do so</p>



<a name="178407403"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178407403" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178407403">(Oct 17 2019 at 18:21)</a>:</h4>
<p>for now I think it might fall in the "TBD" category, since I think it's within the scope of this group to eventually define what the behavior is</p>



<a name="178407530"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178407530" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178407530">(Oct 17 2019 at 18:22)</a>:</h4>
<p>I'm just sharing my personal inclination when I say that I don't think we should catch foreign exceptions in <code>catch_unwind</code>, but I'm happy to argue that at more length when we've reached that point in this project</p>



<a name="178407662"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178407662" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178407662">(Oct 17 2019 at 18:24)</a>:</h4>
<p>I'm definitely opposed for including it in the 0th RFC due to the standard library implications, as well as implementation complications that extend beyond just the compiler's behavior at FFI boundaries</p>



<a name="178409769"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178409769" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178409769">(Oct 17 2019 at 18:46)</a>:</h4>
<blockquote>
<p>- read about half of the PRs, very few of the PR comments</p>
</blockquote>
<p>Do you feel adequately "caught up"? If not, do you have a sense of whether we're failing to capture some important stuff in the repo itself, or is it too early to tell?</p>
<p>(<span class="user-mention" data-user-id="237472">@acfoltzer</span> )</p>



<a name="178410220"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178410220" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Alex Crichton <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178410220">(Oct 17 2019 at 18:51)</a>:</h4>
<p><span aria-label="wave" class="emoji emoji-1f44b" role="img" title="wave">:wave:</span> </p>
<p>Don't have a chance right now to read up on the full discussion but if y'all need me feel free to ping me!</p>



<a name="178410284"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178410284" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178410284">(Oct 17 2019 at 18:51)</a>:</h4>
<p>my sense is that things are heading in the right direction. until I can free up some time to read it all I won't know for sure if anything is missing, but maybe the best way to do that would be to add me as a reviewer on the PR that emerges between <a href="https://github.com/rust-lang/rust/issues/9" target="_blank" title="https://github.com/rust-lang/rust/issues/9">#9</a> and <a href="https://github.com/rust-lang/rust/issues/11" target="_blank" title="https://github.com/rust-lang/rust/issues/11">#11</a>?</p>



<a name="178410541"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178410541" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178410541">(Oct 17 2019 at 18:54)</a>:</h4>
<blockquote>
<p>for now I think it might fall in the "TBD" category, since I think it's within the scope of this group to eventually define what the behavior is</p>
</blockquote>
<p>Note that RFC 0th says that it is not a goal of this group to define the behavior.</p>



<a name="178410641"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178410641" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178410641">(Oct 17 2019 at 18:55)</a>:</h4>
<blockquote>
<p>I'm definitely opposed for including it in the 0th RFC due to the standard library implications, as well as implementation complications that extend beyond just the compiler's behavior at FFI boundaries</p>
</blockquote>
<p>This has been repeated a couple of times. What's the complication of adding something to the standard library? We do that all the time.</p>



<a name="178411072"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178411072" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178411072">(Oct 17 2019 at 18:59)</a>:</h4>
<p><span class="user-mention" data-user-id="237472">@acfoltzer</span>  ^^</p>



<a name="178411085"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178411085" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178411085">(Oct 17 2019 at 18:59)</a>:</h4>
<p>Well, for the 0th RFC, we want to be so minimal that we do not need further bikeshedding. The ABI string <code>"C unwind"</code> is, I think, at that point; but a new <code>std</code> addition is not.</p>



<a name="178411239"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178411239" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178411239">(Oct 17 2019 at 19:01)</a>:</h4>
<p>yeah, that's my sense as well regarding adding to the standard library, but I'm not experienced in the process of moving such things through</p>



<a name="178411793"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178411793" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178411793">(Oct 17 2019 at 19:06)</a>:</h4>
<blockquote>
<blockquote>
<p>for now I think it might fall in the "TBD" category, since I think it's within the scope of this group to eventually define what the behavior is</p>
</blockquote>
<p>Note that RFC 0th says that it is not a goal of this group to define the behavior.</p>
</blockquote>
<p>I hadn't seen this; I suppose this is the relevant part of <a href="https://github.com/rust-lang/rust/issues/11" target="_blank" title="https://github.com/rust-lang/rust/issues/11">#11</a>?</p>
<blockquote>
<ul>
<li>And perhaps to enable native exceptions to propagate across Rust frames</li>
<li>But not to allow catching or throwing native exceptions from Rust code</li>
</ul>
</blockquote>



<a name="178411855"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178411855" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178411855">(Oct 17 2019 at 19:07)</a>:</h4>
<p>I'm fine with this split personally, as I think the issue you bring up in <a href="https://github.com/rust-lang/rust/issues/65441" target="_blank" title="https://github.com/rust-lang/rust/issues/65441">https://github.com/rust-lang/rust/issues/65441</a> would be addressed by the former point</p>



<a name="178412031"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178412031" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178412031">(Oct 17 2019 at 19:09)</a>:</h4>
<p>other than Katharina's talk from last year's RustConf, I'm unaware of anyone who's trying to actually catch foreign exceptions</p>



<a name="178412182"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178412182" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178412182">(Oct 17 2019 at 19:10)</a>:</h4>
<p>and while it's not a point that I'm personally too invested in, adding foreign exception handling to <code>catch_unwind</code> should raise some major red flags in terms of how it would constrain the Rust panic mechanism</p>



<a name="178412533"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178412533" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178412533">(Oct 17 2019 at 19:15)</a>:</h4>
<p>Note that most of the complexity is introduced by allowing foreign exceptions to unwind through Rust</p>



<a name="178412619"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178412619" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178412619">(Oct 17 2019 at 19:16)</a>:</h4>
<p>IIUC you are proposing to have catch_unwind not catch any foreign exceptions, but which behavior to pick there is not a complexity source</p>



<a name="178412696"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178412696" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178412696">(Oct 17 2019 at 19:17)</a>:</h4>
<blockquote>
<p>and while it's not a point that I'm personally too invested in, adding foreign exception handling to catch_unwind should raise some major red flags in terms of how it would constrain the Rust panic mechanism</p>
</blockquote>
<p>As I see it, it does not. It would just mean that <code>catch_unwind</code> needs to support both</p>



<a name="178412703"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178412703" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178412703">(Oct 17 2019 at 19:17)</a>:</h4>
<p>But they can be independent</p>



<a name="178412810"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178412810" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178412810">(Oct 17 2019 at 19:18)</a>:</h4>
<p>Maybe it would be better to attack the problem of catching foreign exceptions using a different API (e.g. <code>catch_foreign_exception(|| ...)</code> or similar - that's something I might be on board with</p>



<a name="178412825"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178412825" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178412825">(Oct 17 2019 at 19:19)</a>:</h4>
<p>but at that point we are just talking syntax, because the real issue is how to support foreign exceptions in the first place</p>



<a name="178412918"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178412918" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178412918">(Oct 17 2019 at 19:20)</a>:</h4>
<p>and all the perils mentioned for <code>catch_unwind</code> in the RFC would still apply, that is, <code>catch_foreign_exception</code> might catch all, some, or none, of the foreign exceptions, depending on the platform</p>



<a name="178412999"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178412999" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178412999">(Oct 17 2019 at 19:21)</a>:</h4>
<blockquote>
<p>other than Katharina's talk from last year's RustConf, I'm unaware of anyone who's trying to actually catch foreign exceptions</p>
</blockquote>
<p>If you want to spawn a thread that does a computation that might throw a foreign exception, without a way to catch them, they bring down your whole application</p>



<a name="178413086"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413086" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413086">(Oct 17 2019 at 19:22)</a>:</h4>
<p>So you need to at least shim your computation in some foreign code that allows you to catch the exception to prevent that - or use a process or something like that.</p>



<a name="178413176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413176">(Oct 17 2019 at 19:23)</a>:</h4>
<p>with this many unresolved questions, doesn't it make sense to not try tackling this for the 0th RFC?</p>



<a name="178413247"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413247" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413247">(Oct 17 2019 at 19:24)</a>:</h4>
<p>or, put differently, what is the harm that you see coming if we do not have this in the 0th RFC?</p>



<a name="178413258"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413258" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413258">(Oct 17 2019 at 19:24)</a>:</h4>
<p>None of that (catching foreign exceptions) sounds like the original problem the working group set out to solve.</p>



<a name="178413293"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413293" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413293">(Oct 17 2019 at 19:25)</a>:</h4>
<p>The harm I see is that the WG won't end up fulfilling its goal of offering a way to interface with the platform ABI</p>



<a name="178413420"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413420" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413420">(Oct 17 2019 at 19:26)</a>:</h4>
<p>The 0-th RFC now says that "C unwind" is not guaranteed to implement the platform ABI, but that we intend to do so. The 1-th RFC might say that we only implement the produce part. The 2-th RFC the consume part, but maybe due to decisions in the 0-th RFC, we can't implement the consume part.</p>



<a name="178413446"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413446" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413446">(Oct 17 2019 at 19:27)</a>:</h4>
<p>if we changed "<del>But not</del> And perhaps to allow catching or throwing native exceptions from Rust code" would that help?</p>



<a name="178413470"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413470" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413470">(Oct 17 2019 at 19:28)</a>:</h4>
<p>For me, this looks much more complex than just saying that we add "C unwind" on Linux only on RFC 1, and on Windows on RFC 2, and on Mac on RFC 3</p>



<a name="178413535"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413535" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413535">(Oct 17 2019 at 19:28)</a>:</h4>
<p>Such an approach has less unknowns because we can verify at each step that the ABI actually works</p>



<a name="178413625"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413625" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413625">(Oct 17 2019 at 19:29)</a>:</h4>
<p>Some systems ABIs allow things like foreign exceptions, I don't want the feature to land in a position where that cannot be supported</p>



<a name="178413717"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413717" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413717">(Oct 17 2019 at 19:30)</a>:</h4>
<p>If we leave the propagation of foreign exceptions as UB, I don't see why we couldn't specify it later.</p>



<a name="178413787"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413787" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413787">(Oct 17 2019 at 19:31)</a>:</h4>
<p>For example, what would we specify that to for targets for which unwinding does not make sense at all ?</p>



<a name="178413854"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413854" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413854">(Oct 17 2019 at 19:32)</a>:</h4>
<p>that's kind of a consequence of adding "C unwind" to all targets in RFC 0, leaving everything as UB, and then worrying about targets later</p>



<a name="178413925"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413925" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413925">(Oct 17 2019 at 19:33)</a>:</h4>
<p>I think we're seeing things along different axes of complexity; I see way fewer design questions to answer and less implementation work to be done if we only consider the behavior of Rust exceptions as a first step. If the RFCs instead proceeded by having complete ABI interop, but on one platform at a time, that means we would have to frontload almost all of the design work for a complete solution</p>



<a name="178413929"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413929" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413929">(Oct 17 2019 at 19:33)</a>:</h4>
<p>What do you mean by "what would we specify that to"?</p>



<a name="178413993"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178413993" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178413993">(Oct 17 2019 at 19:34)</a>:</h4>
<p>We <em>wouldn't</em> specify it, that's the point.</p>



<a name="178414034"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414034" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414034">(Oct 17 2019 at 19:34)</a>:</h4>
<p>If unwinding doesn't make sense, then why would we specify foreign exception unwinding?</p>



<a name="178414046"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414046" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414046">(Oct 17 2019 at 19:34)</a>:</h4>
<p>So now we have added a language feature that says "C + unwinding" but that cannot be implemented meaningfully for a target, yet code that uses the feature is not UB</p>



<a name="178414077"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414077" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414077">(Oct 17 2019 at 19:35)</a>:</h4>
<p>That's an interesting misinterpretation of what I said.</p>



<a name="178414116"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414116" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414116">(Oct 17 2019 at 19:35)</a>:</h4>
<p>I don't think you understood what I said</p>



<a name="178414174"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414174" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414174">(Oct 17 2019 at 19:36)</a>:</h4>
<p>Why would we add a language feature that's correct to use, has unspecified behavior, but cannot ever work ?</p>



<a name="178414181"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414181" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414181">(Oct 17 2019 at 19:36)</a>:</h4>
<p>I think neither of us is understanding where the other is coming from. I'm about to board a plane, so I'll have to continue this another time.</p>



<a name="178414187"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414187" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414187">(Oct 17 2019 at 19:36)</a>:</h4>
<p>It is not correct to  use <code>"C unwind"</code> on a target that does not support unwinding.</p>



<a name="178414196"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414196" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414196">(Oct 17 2019 at 19:36)</a>:</h4>
<p>RFC 0 does not say that</p>



<a name="178414212"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414212" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414212">(Oct 17 2019 at 19:37)</a>:</h4>
<p>its says that it has unspecified behavior, and it emphasizes that it is not UB</p>



<a name="178414220"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414220" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414220">(Oct 17 2019 at 19:37)</a>:</h4>
<p>It absolutely can work. Your assertion that it "cannot ever work" does not make sense to me.</p>



<a name="178414227"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414227" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414227">(Oct 17 2019 at 19:37)</a>:</h4>
<p>One possible behavior is compiler-error.</p>



<a name="178414288"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414288" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414288">(Oct 17 2019 at 19:38)</a>:</h4>
<p>Another is...whatever happens already when <code>unwind(allowed)</code> is used on such a platform.</p>



<a name="178414312"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414312" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414312">(Oct 17 2019 at 19:38)</a>:</h4>
<p>"Unspecified" is specifically allowed to have a wide range of behaviors.</p>



<a name="178414321"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414321" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414321">(Oct 17 2019 at 19:38)</a>:</h4>
<blockquote>
<p>One possible behavior is compiler-error.</p>
</blockquote>
<p>Is it? According to the definition we agreed on we said that it does something in the abstract machine, we just not say what it is.</p>



<a name="178414324"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414324" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414324">(Oct 17 2019 at 19:38)</a>:</h4>
<p>And to change over time</p>



<a name="178414328"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414328" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414328">(Oct 17 2019 at 19:38)</a>:</h4>
<p>For that to happen, it needs to compile.</p>



<a name="178414365"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414365" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414365">(Oct 17 2019 at 19:39)</a>:</h4>
<p>That is a good point; <span class="user-mention" data-user-id="116009">@nikomatsakis</span> what is your perspective on whether unspecified behavior "must compile"?</p>



<a name="178414382"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414382" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414382">(Oct 17 2019 at 19:39)</a>:</h4>
<p>If it is not required to compile, then I'd be in with it.</p>



<a name="178414389"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414389" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414389">(Oct 17 2019 at 19:40)</a>:</h4>
<p>In any case, though, in previous RFC discussions we have agreed that <code>"C unwind"</code> would not be one of the cross-platform always-available ABIs</p>



<a name="178414454"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414454" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414454">(Oct 17 2019 at 19:40)</a>:</h4>
<p>so, we have two axes here I think:</p>
<ol>
<li>How rich is our support for the ABI?</li>
<li>Which target triples are supported?</li>
</ol>



<a name="178414466"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414466" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414466">(Oct 17 2019 at 19:40)</a>:</h4>
<p>I certainly wouldn't expect it to be.</p>



<a name="178414476"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414476" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414476">(Oct 17 2019 at 19:40)</a>:</h4>
<p>I thought so to as well, which is why I was surprised for RFC 0 not to mention it.</p>



<a name="178414499"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414499" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414499">(Oct 17 2019 at 19:40)</a>:</h4>
<p>Note, too, that our roadmap started out with that platform-support table, with "not in scope" for all but Win/Mac/Linux</p>



<a name="178414510"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414510" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414510">(Oct 17 2019 at 19:41)</a>:</h4>
<p>Well, it's just a draft; let's add it :D</p>



<a name="178414532"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414532" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414532">(Oct 17 2019 at 19:41)</a>:</h4>
<p>I don't expect that RFC 0 would commit to <code>"C unwind"</code> being available on <strong>any</strong> particular target triple, except maybe 64-bit Linux just to have an example case</p>



<a name="178414534"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414534" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414534">(Oct 17 2019 at 19:41)</a>:</h4>
<p>(Also, please pardon my not being up to date on the terminological discussion regarding "UB" versus "unspecified".)</p>



<a name="178414616"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414616" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414616">(Oct 17 2019 at 19:42)</a>:</h4>
<blockquote>
<p>Well, it's just a draft; let's add it :D</p>
</blockquote>
<p>I left a comment asking for clarification. I'll add it instead.</p>



<a name="178414646"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414646" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414646">(Oct 17 2019 at 19:42)</a>:</h4>
<blockquote>
<p>(Also, please pardon my not being up to date on the terminological discussion regarding "UB" versus "unspecified".)</p>
</blockquote>
<p><span class="user-mention" data-user-id="239881">@Josh Triplett</span> Fortunately, we've written up a document in the repo, so at least we have a place to keep the "latest and greatest shared understanding"!</p>



<a name="178414692"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414692" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414692">(Oct 17 2019 at 19:43)</a>:</h4>
<p>I'm aware; just haven't had a chance to read it. Still on vacation, about to get on a plane to Athens.</p>



<a name="178414699"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414699" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414699">(Oct 17 2019 at 19:43)</a>:</h4>
<p>:)</p>



<a name="178414953"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414953" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414953">(Oct 17 2019 at 19:46)</a>:</h4>
<p>I say before that I would be in if we can choose the unspecified behavior to not compile later on, that still holds, but I would prefer if we were not to add any code that would compile and that we later on need to prevent from compiling</p>



<a name="178414989"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178414989" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> gnzlbg <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178414989">(Oct 17 2019 at 19:46)</a>:</h4>
<p>But adding the "C unwind" on some platforms only should make sure that we only add it for those platforms for which we can actually implement it, so that should be fine</p>



<a name="178415864"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178415864" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178415864">(Oct 17 2019 at 19:56)</a>:</h4>
<blockquote>
<p>choose the unspecified behavior to not compile later on, that still holds, but I would prefer if we were not to add any code that would compile and that we later on need to prevent from compiling</p>
</blockquote>
<p>That's a good point. And, I think, definitely a divergence from the C++ definition of "unspecified" (I will check).</p>



<a name="178416009"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178416009" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178416009">(Oct 17 2019 at 19:58)</a>:</h4>
<p>Yeah, in that context, it's probably better to define "unspecified" as "compiles, but behavior may change, and for any two behaviors in the range of possibilities, the actual behavior can switch from one to the other at any time"</p>



<a name="178416073"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178416073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178416073">(Oct 17 2019 at 19:59)</a>:</h4>
<p>rather than trying to include a concept of monotonic-change in the definition, from does-not-compile to compiles, but not vice-versa</p>



<a name="178884318"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178884318" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178884318">(Oct 23 2019 at 18:55)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> <span class="user-mention" data-user-id="237472">@acfoltzer</span> It looks like I won't be able to meet tomorrow until after the lang team meeting.</p>



<a name="178884381"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178884381" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178884381">(Oct 23 2019 at 18:56)</a>:</h4>
<p>I have a flight mid-day Friday, but it's conceivable I could chat while waiting for my plane....</p>



<a name="178892444"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178892444" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178892444">(Oct 23 2019 at 20:19)</a>:</h4>
<p>I won't be able to make it any later than the usual time tomorrow; I'm on Eastern time this week and my afternoon is pretty full. do we have a calendar event set up?</p>



<a name="178893566"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178893566" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178893566">(Oct 23 2019 at 20:29)</a>:</h4>
<p>I am available for about three hours starting now, it turns out.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178893734" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> acfoltzer <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178893734">(Oct 23 2019 at 20:30)</a>:</h4>
<p>not a good time for me, unfortunately. but I also haven't had time to do much on the project, so you shouldn't let that stop y'all <span aria-label="slight smile" class="emoji emoji-1f642" role="img" title="slight smile">:slight_smile:</span></p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/210922-project-ffi-unwind/topic/meeting%20time/near/178898186" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> BatmanAoD (Kyle Strand) <a href="https://rust-lang.github.io/zulip_archive/stream/210922-project-ffi-unwind/topic/meeting.20time.html#178898186">(Oct 23 2019 at 21:23)</a>:</h4>
<p>That's reasonable! Hope your deliverable is going well</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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